Auckland Action Against Poverty's Alastair Russell says those stuck below the poverty line turn to such drugs out of hopelessness.

"If you are looking at employment that offers you low wages, low conditions, no security of hours and no way forward, then you are effectively excluded from the 'rock star economy' the Government keeps on talking about."

Mr Russell says the Government must commit to measures to address poverty and health underfunding if it wants to reduce drug-related harm.

"At the absolute root of the problem is a system that doesn't care. There is no intention of addressing poverty," he told Newshub.

"Mental health is vastly underfunded - has been for a very long time. The outcomes of that are all too predictable, and very, very sad and tragic when they do occur."

He wants the Government to invest in more safe, affordable homes, and lift the incomes of beneficiaries and those below the poverty line.